A Merton woman who stepped in to stop a fight on the Wimbledon-Croydon tram was stabbed in the thigh.

British Transport Police are appealing for witnesses after the incident, which took place at the Ampere Way tramstop in Croydon at 11.40pm on Thursday August 30.

Detective Sergeant Bob Stokoe, the investigating officer, said the woman had stepped in to calm down an altercation between a group of men.

He said: "The 24-year-old woman, from Merton, had been out with friends and was waiting for a tram as the fight broke out.

"In an attempt to diffuse the heated situation, the victim was then assaulted by members of the group, causing her to fall to the floor. Moments later, she realised that she had been stabbed in the thigh.

"The woman was taken to hospital by ambulance and was discharged shortly after being treated for a small stab wound. No weapon was left at the scene."

The group of youths detectives are keen to speak to are described as "black and mixed race boys". One youth in particular had distinctive hazel eyes.

DS Stokoe is asking for the public's help and urging anyone with information to come forward:

"This attack left the victim requiring hospital treatment, not to mention causing her considerable shock and emotional distress.

"We are carrying out an extensive investigation into this attack, including making local enquiries and carrying out regular patrols in the area. We have also requested CCTV footage and are keen to speak with anyone who may have information key to our investigation."

Anyone with information is asked to contact British Transport Police on 0800 40 50 40 quoting B7/LSA of 2/09/2012. Information can also be given to the independent charity Crimestoppers, anonymously on 0800 555 111.